Grain dryer



Fb. 23, 1950 M, w GILMORE ET AL 2,925,666

GRAIN DRYER 3 Sheets-Sheet 1 Filed Feb. 5, 1958 I m M w w 3 l. W 1 w a wm p 5 v 0 flfl V I I L M v M ill k 0/7 n A? J z fifia 9 w w ,4 y M a w 7z E bEII i WLEL! Ii .7 m U L g M JQLW a a; v I w M 1 a a t m 0 L L W 4 HW J P INVENTQRS Me WWW 67/ an:

BY r/a f e Feb. 23,1960

Filed Feb. 3, 1958 M. w. GlLMORE ET L GRAIN DRYER 3 Sheets-Sheet 2INVENTOR Mam/014! Mmare Arm/7744 Feb. 23, 1960 M. w. GILMORE ET AL GRAINDRYER Filed Feb. 3, 1958 3 Sheets-Sheet 3 INVENTOM Mam/1r; 14! Mme/e BYb1; 52b! 62 V Afro/we y.

United States Patent GRAIN DRYER Merwin W. Gilmore, Clay Center, andHarlan H. Tatge, Herington, Kans.

Application February 3, 1958, Serial No. 712,844 11 Claims. (Cl. 34-102)This invention relates to new and useful improvements in grain dryers,and has particular reference to grain dryers wherein grain is circulatedcontinuously through a chamber through which heated air is forced.

An important object of the present invention is the provision of novelmeans whereby the thickness of the layer or bed of grain through whichthe heated air is forced is maintained uniform over its entire area,whereby the heated air passes uniformly through all parts of the grainbed and the efliciency and speed of the drying operation is therebyenhanced.

Another important object is the provision of novel agitating means formaintaining uniform flow of grain in all parts of the grain bed. Theincrease in volume of the air due to the heating thereof, plus the addedvolume of the moisture vapor removed from the grain itself, oftencreates localized pressure zones or areas within thebody of the grainmass, and these pressure Zones often inhibit and sometimes completelyshut off the flow of grain in those zones, with the result that thecapacity and eiiiciency of the machine is seriously reduced, and withthe dangerthat the grain will be cooked and damaged by prolonged orexcessive exposure to heat without free circulation of air thereabout.

Still another object is the provision of novel means whereby the rate ofcirculation of the grain through the drying chamber may be closelyregulated, whereby to provide optimum conditions for grains of differenttypes, or for grains of different degrees of wetness.

Another object is the provision of a power driven device forrecirculating the grain in the dryer, said circulating device beingoperable also to discharge the grain, after it has been dried, to atruck or the like for transpontation.

Other objects are simplicity and economy of construction, in order thatthe device may be sold for a much smaller price than comparableequipment of similar capacities, efficiency and dependability ofoperation, and adaptability for use in a wide variety of applicationsand conditions.

With these objects in view, as well as other objects which will appearin the course of the specification, reference will be had to thedrawing, wherein:

Fig. 1 is a central vertical sectional view through a grain dryerembodying the present invention, with parts I left in elevation,

of one of the louvered walls of the drying chamber, and

'Fig.'9is a sectional'view taken on line IX--IX of Fig. 8.

Like reference numerals apply to similar parts throughout the severalviews, and the numeral 2 appliesgenerally to an outer housing having anupper cylindrical portion 4- open at the top, and a lower conicalportion 6, said conical portion terminating at its lower end in a cylindrical well 8 of reduced diameter, said well having a horizontal bottomwall 10. Said outer housing is supported above a rectangular angle ironframe 12 by legs 14, and said frame is in turn supported byground-engaging legs 16. Substantially the entire area of cylindricalwall 4 of the outer housing has louvers 18 formed therein as-best shownin Figs. 8 and, 9, said louvers being formed by slitting the wallhorizontally at spaced intervals, and forcing the wall area immediatelybelow each of said slits outwardly as shown. Said louvers open upwardly,and outwardly from the general plane of the Wall. for a purpose whichwill presently appear.

Supported within outer housing 2, at the juncture of the cylindricalportion 4 and conical portion 6 thereof, is a horizontal spider 20 whichis formed of channel irons and which may be of any suitable design. Asshown, it comprises a square central frame, 22 having four arms 24extending radially outwardly therefrom and secured at their outer endsto conical wall 6 at the upper edge thereof.

An inner housing 26 is disposed within housing 2 and is supported onspider 20. Said innerhousing comprises a cylindrical portion 28 disposedconcentrically with wall 4 of housing 2 and supported at its lower endon spider arms 24, being affixed thereto by brackets 30, and an upperportion 32 of conical shape, said conical portion being disposed belowthe top of wall 4 of the outer housing. Substantially the entire areao'fthe inner housing, including both the cylindrical and conical portionsthereof, has louvers 18 formed therein, these louvers being identical tothose formed in outer housing wall 4 except that the louvers of theinner housing open inwardly.

A cylindrical auger tube 34 extends vertically and axially through innerhousing 26, extending at its upper end well above outer housing 2, andterminating at its lower end just above the cylindrical well 8 of theouter housing. Adjacent its lower end, said tube passes centrallythrough the square frame 22 of spider 20, and is supported by a clampring 36 afiixed thereto, and a plurality of radial arms 38 fixed attheir inner ends to said clamp ring and at their ,outer ends to frame22. Adjacent its upper end, auger tube 34 extends through the upper endof the conical portion 32 of the inner housing, and is supported by aclamp ring 40 aflixed thereabout, and a plurality of radial arms 41afiixed at their inner ends to said clamp ring and at their outer endsto wall 4 of the outer housing. At its extreme upper end, tube 34 has aninverted cup-shaped cap 42 fitted rotatably thereover. Said cap has atop end wall 44, and is adapted to serve as a valve as will presently bedescribed. An auger 46 is carried rotatably in tube 34, and is operableto propel grain upwardly through said tube when rotated. The shaft 48 ofsaid auger extends upward through end wall 44 of the cap, and isjournalled in a bearing 50 'aflixed to said cap. At its lower end, theauger is provided with a reduced extension shaft 52 which projectsdownwardly through the floor wall 10 of well 8, and is journalled in abearing 54 aflixed to the lower surface of said wall. Attached to thelower end of said extension shaft is a belt pulley 56, by means of whichthe auger may be operably driven. It will be apparent that as the augeris turned, grain will be elevated thereby from well 8 through tube 34.

Referring principally to Figs. 5 and 6, it will be seen that the upperend of auger tube 34 is provided with a pair of diametrically oppositeopenings 58 formed in the wall thereof within the vertical limits of cap42. A corresponding pair of openings 60 are formed in said cap, and areadapted to be brought into registering relation with openings 58 byturning the cap on the auger tube. Thus grain brought up through thetube is dischargedoutwardly through openings 58 and 60, and is deflecteddownwardly into housing 2 by a pair of deflectors'62 affixed to the capand being spaced outwardly from openings 60 of said cap. A third opening64 is formed in cap42 intermediate openings 60, opening 64 communicatingwith a spout 66 which is angled outwardly and downwardly and which isrigidly aflixed to cap 42. Pivoted at 68 to the outer end of spout 66 isa troughlike spout extension 70 which extends outwardly from outerhousing wall 4 and rests by gravity on the upper edge'thereof. Adjacentthe outer end of said spout extension, a depending handle 72 is attachedthereto which extends downwardly to a point such that it may be reachedby a person standing on the ground. It will be seen therefore that spout66 and it extension 70 may be movedto extend in any direction from augertube 34, and that in so doing, cap'42 is turned on said auger tube.Referring to Fig. 5, it will be seen that when cap 42 is turned 90degrees from the position shown, one of the openings 58 of the augertube will be closed off by the cap and cap opening 64 will be broughtinto registry with the other of tube openings 58. Thereupon grainelevated by the auger will be discharged into spout 66. This setting ofthe cap, which may also be termed a valve, is of course used when thedrying of the grain is complete and it is desired to discharge saidgrain into a truck or the like. A

A large tubular air conduit 74 is interconnected into inner housing 26adjacent the lower edge of the cylindrical wall 28 of said housing. Saidconduit extends horizontally outwardly through the cylindrical wall 4 ofthe outer'housing 2, and outwardly from said outer housing, beingprovided at its outer end with a flared air intake ring 76. Within themouth of said conduit is disposed a-blower fan 78 which is mounted on ashaft 80 journalled in bearings 82 mounted on a spider 84 which bridgesintake ring 76. Mounted on the outer end of said shaft isa'pulley 86which is operatively connected by a belt 88 with a pulley 90 fixed on;the output shaft 92 of a gasoline engine 94. Said engine is mounted on ahorizontal extension 96 of frame 12. It will be apparent that the bloweralso could be operated by an electric motor "or other prime movermounted on the frame, or 'by a belt connection to the usual powertake-off of a farm {tractor or the like. A second belt pulley 98 is alsomounted on engine shaft 92. A belt 106 is trained around pulley'98,extends downwardly and is trained about a pair of pulleys 102 carriedrotatively by frame extension 96, and then extends horizontally and istrained about pulley 56 mounted on auger extension shaft 52. Thus itwill be seen that both the blower 78 and auger 46 are powered by engine94. The relative speeds of the blower and auger are governed by therelative sizes of the various pulleys engaged by belts 88 and 100. Alsomounted in conduit 74, just inwardly from blower 78, is a burner 104which is supplied with gas or other suitable fuel through pipe 106. Theflame of thisburner is adapted to heat the air forced inwardly throughconduit 74 by blower 78.

In use, the grain to be dried is dumped into the top of outer housing 2,whereby it fills the annular chamber -108 between the cylindricalportions of the inner and outer housings, and also passes downwardlythrough the conical portion 6 of the outer housing into well 8. The

' grain should also coverthe upper conical portion 32 of the innerhousing to a depth equal to the radial thickness' of chamber 108 for apurpose which will appear.

Valve cap 42 is positioned as shown in Figs. Sand 6. Engine 94 is thenstarted to drive'blower 78 and auger "46,"and burner 104 is lighted.Heated air will thereupon be f orcedthrough conduit. interior of innerwas housing 26, outwardly through the louvers 18 of said inner housing,through the bed of grain in chamber 108 and over the top of the innerchamber, and thence to the atmosphere either through the top of theouter housing, or through the louvers 18 of said outer housing, and thegrain will be subjected to the drying action of the heated air.

At the same time, grain is continuously elevated from well 8 throughauger tube 34 by auger 46, and is discharged from the upper end thereoffor recirculation. The grain is thus in constant circulation downwardlythrough chamber 108 and upwardly through the auger tube, and thiscirculation is maintained until the grain has reached the desired degreeof dryness. It will be understood that the generating angle of theconical upper portion 32 of the inner housing is equal to the normalangle of repose of grain deposited in a pile, so that grain dischargedfrom the upper end of the auger tube will arrange itself in a layer ofsubstantially uniform thickness, and further that the normal grain loadof the dryer is such that the thickness of the grain bed over cone 32 issubstantially equal to the radial thickness of annular chamber 108between the inner and outer housings. In this manner, the heated airpasses at all points through a grain bed of uniform thickness, and willtherefore be distributed evenly over the entire area of said grain bed.This even distribution of air is essential to efiicient drying, sincethe drying action could not proceed evenly if portions of the grain bedreceived deficient quantities of hot air, and further since excessivehot air concentrated at thin portions of the bed would create a dangerof burning or cooking the grain in those portions.

Since the drying rate best suited for diiferent grains, or for grains ofdifferent degrees of wetness, may vary substantially, there is providedalso a means for closely regulating the rate of circulation of the grainin the dryer. This means includes a tubular extension 110 for auger tube34, said extension tube being fitted te1escopingly about the lowerportion of said auger tube and being vertically slidable thereon.Pivoted at 112 to the upper portion of said extension tube is the lowerend of a link 114, the upper end of said link being pivoted at 116 tothe free end of a crank 118 which is fixed to a horizontal shaft 120.Said shaft extends horizontally outwardly to a point external to outerhousing, being journalled in the central frame 2'2 of spider 20, and inthe lower conical portion 6 of the outer housing. Said shaft has affixedto its extended end a manually operable crank 122 and a toothed wheel124, the latter being releaseably engaged by a dog 126 pivoted at 128 toone of legs 14 of the'outer housing. It will be seen that by releasingdog 126 and turning crank 122, extension tube 110 may be selectivelyraised and lowered between an upper position, asshown, wherein the lowerend thereof is disposed above well 8, to a lower position wherein itextends substantially to the bottom of said well, or to any of a seriesof intermtdiate positions. In this manner the amount of grain picked upby the auger in each revolution may be varied, and the circulation rateof the grain through the dryer very closely regulated. Another use ofextension 110 occurs when, for any reason, it is desired to stop theauger while the dryer is loaded. In this case, while the auger is stillturning, extension 110 is fully lowered, and anger 46 is continued inoperation until the auger tube is emptied. Then, when it is eventuallydesired to again start the auger, it may be started under a no-loadcondition. When the auger tube is full, great power is required to startthe anger, with the result that engine 94 is overloaded or stalled;

burner 104, with a subsequent increase of pressure in inner housing 26.Furthermore, moisture evaporated from the grain as the hot air passestherethrough adds a great volume'of vapor which adds still furtber tothe internal pressure within the mass of grain. It is believed to bethis pressure which has heretofore created ineflicient circulation ofgrain in dryers of this general type. That is, the increased pressuretends to create localized zones of high pressure which inhibit andactually completely shut off the flow of grain. This of course reducesthe efiiciency of the drying operation, and creates a danger of burningor cooking the grain, as previously described. As a matter of fact, inthe present dryer, before provisions were made to correct it,circulation of grain was found to be decreased gradually duringoperation, sometimes to the point of almost complete cessation, due tothe above described pressure increase. The effect is most noticeable andapparent when the grain being dried is quite wet. It also occursprincipally at points of flow restriction, namely in the lower portionof chamber 108 where it empties into the conical portion 6 of the outerhousing. Another point of stoppage has been found to exist in the well8, where the outward pressure of the auger on the grain has a tendencyto pack the grain against the walls of the well in a hard,non-circulating mass which prevents the entry of other grain.

In order to overcome this ditficulty, we have utilized a novel agitatorpowered by the rotation of auger 46. Fixed rigidly to auger shaftextension 52, just above the floor of well 8, is a circular eccentriccam 130 (see Figs. 3 and 4). Said cam is engaged rotatably in the hub132 of a fiat circular plate -134 which rests slidably against the uppersurface of floor 10. Cam130 is eccentric to shaft 52, but concentricwith plate 134. Thus as shaft 52 rotates to turn the auger, cam 130imports an orbital movement to plate 134. Fixed to the edges. of plate134, at regularly spaced intervals about the periphery thereof, are thelower ends of a plurality of rods 136. Said rods extend verticallyupwardly through well 8 to a point above the upper end of said well, andare welded or otherwise fixed to the external surface of a horizontallydisposed ring 138 just above said well. Above ring 138, rods 136 areangled radially outwardly and upwardly, extending upwardly throughconical portion 6 of the outer housing, between the arms 24 of spider20,. and are fixed at their upper ends to a horizontally disposed circular agitator ring 140 resting on the upper edges of arms 24. Saidagitator ring surrounds inner housing 26, its diameter beingintermediate that of the inner and outer housings. Agitator ring 140 ofcourse moves orbitally together with plate 134, and therefore agitatesor stirs the grain in the lower portion of chamber 108. This has beenfound quite effective in breaking up any pockets or zones of highpressure in the grain in this area, and to promote the free flow ofgrain. The dryer has been thoroughly tested with this agitator, andgrain circulation has been found to remain free and continuous even withgrains far wetter than would normally ever be encountered. The lowerportions of rods 136, between ring 138 and plate 140, form an opencage-like formation which orbits in the zone directly adjacent theauger, and effectively prevents the packing or lodgement of grain in thewell. The diameter of ring 138, and the degree of eccentricity of cam130, must of course be such that auger tube extension 110 will notinterfere with the movement of said ring even when said extension ispartially or completely lowered.

Another feature promoting free circulation of air is the formation oflouvers 18 in the housing walls. Referring to Fig. 9, it will be seenthat each louver provides a narrow slit opening 142 which is too narrowfor the grain to enter or become jammed therein, which would of coursetend to shut off the flow of air. Moreover, referring to Fig. 1, it willbe seen that the louvers open outwardly from the general planes of thewalls forming chamber 108 through which the grain circulates, andupwardly in a direction opposite to the travel of the grain. Thus thegrain always travels away from, not

6 toward, the openings 142. This further prevents the grain from beingjammed or clogged in the air openings.

While we have shown and described a specific embodiment of ourinvention, it will be readily apparent that many minor changes ofstructure and operation could be made without departing from the spiritof the invention as defined by the scope of the appended claims, and itis accordingly desired that our patent protection extend and cover allsubject matter falling properly within the scope of said claims.

What we claim as new and desire to Patent is:

1. A grain dryer comprising a frame, an outer cylindrical housingcarried by said frame, said outer housing being open at the top andhaving a bottom closure with a central well of reduced diameter formedtherein, an inner cylindrical housing supported concentrically withinsaid outer housing whereby to form an annular chamber between saidhousings, the lower end of said inner housing being spaced above thebottom closure of said outer housing and having a top closure, a tubeopen at both ends supported vertically and concentrically in saidhousings with its lower end adjacent said well and its upper endextending above the top closure of said inner housing, a conveyordisposed within said tube with its lower end extending below said tubeand operable to elevate grain from said well and to discharge said grainfrom the upper end of said tube, means carried by said frame andincluding a blower operable to deliver heated air under pressure to theinterior of said inner housing, the walls of said inner and outerhousings being perforated whereby to permit the passage of said airtherethrough, and a prime mover carried by said frame and operable todrive said blower and said conveyor.

2. A grain dryer as recited in claim 1 wherein the perforations in saidhousing are formed by portions of the walls of said housings offsetoutwardly with respect to the annular chamber between said housings toform outwardly and upwardly opening apertures narrower than the averagediameter of the kernels of grain to be dried, whereby to preventclogging or jamming of said apertures by said grain.

3. A grain dryer as recited in claim 1 wherein the top closure of saidinner housing is shaped conically coaxially with the housing, and withits apex up, said closure being louvered to permit the passage of airtherethrough, and the angle of the wall thereof to the horizontalcorresponding substantially to the angle of repose of the grain, wherebywhen the dryer is charged with the proper amount of grain, a layer ofgrain of uniform thickness will be disposed at all times over said topclosure, said thickness being equal to the radial thickness of theannular chamber between said housings.

4. A grain dryer as recited in claim 1 wherein said conveyor comprises avertical auger disposed in said tube and extending substantially to thebottom of said well, and with the addition of means operable to extendthe lower end of said tube adjustably from a position substanttially atthe top of said well to a position substantially at the bottom of saidwell, whereby the amount of grain picked up by said auger in eachrevolution thereof may be adjusted.

5. A grain dryer as recited in claim 1 wherein said conveyor comprises avertical auger carried rotatably in said tube and extendingsubstantially to the bottom of said well, and with the addition of atubular extension fitted telescopingly about the lower portion of saidtube and being vertically slidable thereon, and means carried by saidframe and operable to lower said extension adjustably to a positionextending substantially to the bottom of said well.

6. A grain dryer as recited in claim 1 with the addition of a horizontalagitator ring encircling said inner housing and disposed in the lowerportion of said annular chamber, and means operable by said prime moverprotect by Letters 7. A grain dryer as recited in claiml with the addi-{Lion of a plural'ity of rods forming a cylindrical open 'fcage'disposedmovablvwithin said well concentrically with said tube but of largerdiameter than said tube, and wherein said conveyorconstitutes a verticalauger disposed in said tube and extending substantially to the bottom ofsaid well, and means operable by rotation of said auger to impart acircular orbital movement to said sa 81A grain dryer as recited in claim1 with the addition of a plurality of rods forming a cylindrical opencage disposed movably within saidlw ell concentrically with said tubebut of larger diameter than said tube, and wherein said conveyorconstitutes a vertical auger disfp osed insaid tube and extendingsubstantially to the bottom of said well, an eccentric cam fixed to androtatable with said auger, and a member driven by said cam and afiixedto said cage, whereby a circular orbital 'inovemen t is imparftedto saidcage;

9. A grain dryer as recited in claim 1 with the addition of a pluralityof rods forming a cylindrical open cage disposed movably within saidWell concentrically with said tube but of larger diameter than saidtube, and

wherein said conveyor constitutes a vertical auger dis posed in saidtube and extending substantially (to the bottom of said well, aneccentric cam fixed to and rotatable with said auger, and a memberdriven by said cam and afiixed to said cage, whereby a circular orbitalmovement is imparted to said cage, and an agitator ring encircling saidinner housing in the lower portion of said .aeabges annular chamber,said cage rods extendingupwardly and "on w'ardly from said well andbeihgfixed at ttheir upper ends tofsaidagitator ring, whereby; the movementof said cage is imparted also't'o said agitator ring.

10. A grain dryer as recited in claim '1 with the addition of a'valvecap fitted rotatablyover the upper end of said tube and having a spoutaifixed thereto and extending horizontally outwardly past the upper edgeof the outer housing, said valve cap being operable by'rotation thereofto deliver grain discharged by said conveyor selectively downwardly intosaid outer housing, or to said spout.

11. A grain dryer as recited in claim 1 wherein said tube is provided atits upper end with a discharge opening, and with the addition of atubular cap fitted rotatably over theupper end of said tube and having aplurality of openings formed therein, and a spout fixed to said cap andcommunicating with one of the openings thereof, said spout extendingoutwardly over the upper edge'of said outer housing and serving as ameans whereby said cap may be manually rotated, said cap being operablein one position to register the spout opening thereof with the tubeopening, whereby grain discharged by said conveyor will be conveyedthrough said spout, and in an- 'otherposition to register another of thecap openings with the tube opening, whereby grain discharged by theconveyor will fall into said outer housing.

References Cited in the file of this patent UNITED STATES PATENTS

